Seth Klarman, a hedge fund billionaire some call the next Warren Buffett, wrote a letter that made its rounds at the World Economic Forum at Davos. The letter warned that investors should start paying attention to global tensions, rising debt levels and political divides. Marriott International President and CEO Arne Sorenson, Bridgewater Founder and co-chairman Ray Dalio and Blackstone co-Founder and CEO Stephen Schwarzman responded to the letter on "Squawk Box."